Free webp to jpg
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Image MIME Reference
APNG

Animated Portable Network Graphics

image/vnd.mozilla.apng
VS

DICOM Run-Length Encoding

image/dicom-rle
DICOM-RLE

A complete technical comparison of Animated Portable Network Graphics and DICOM Run-Length Encoding — covering compression, feature support, browser compatibility, magic bytes, and when to choose each format.

APNG wins on browser support

Feature Support

Feature APNG DICOM-RLE
Transparency (Alpha) Yes ✕ No
Animation Support Yes Yes
Progressive Loading Yes ✕ No
HDR Support ✕ No Yes
EXIF Metadata Yes ✕ No
ICC Color Profile Yes Yes
Animated Portable Network Graphics
image/vnd.mozilla.apng
Extension
.apng.png
Container PNG Chunk Stream
Compression Deflate (Lossless)
Algorithm
Deflate (zlib)
Color Depth 8-bit (Indexed), 24-bit (TrueColor), 32-bit (RGBA)
Developed by Mozilla Corporation (Stuart Parmenter & Vladimir Vukićević)
Released 2004
Magic Bytes
89 50 4E 47 0D 0A 1A 0A
Full APNG reference →
DICOM Run-Length Encoding
image/dicom-rle
Extension
.dcm.dicom
Container DICOM (PS3.10)
Compression Lossless (RLE)
Algorithm
Run-Length Encoding (RLE)
Color Depth 8-bit, 16-bit, 24-bit
Developed by National Electrical Manufacturers Association (NEMA) / ACR
Released 1993
Magic Bytes
44 49 43 4D (at byte offset 128)
Full DICOM-RLE reference →

Browser Support Comparison

Browser APNG DICOM-RLE
Chrome Chrome
✓ 59
 ✕
Firefox Firefox
✓ 3
 ✕
Safari Safari
✓ 8
 ✕
Edge Edge
✓ 79
 ✕
IE IE (Legacy)
✕ ✕
APNG

APNG Strengths

  • Supports 8-bit alpha transparency, completely solving the ugly 'white halo' problem inherent to GIFs
  • Gracefully degrades; viewers that do not support APNG will render a perfectly valid, static PNG of the first frame
  • Provides lossless compression that retains absolute pixel-perfect quality for UI elements and line art
Limitations
  • Because it relies on lossless Deflate compression, file sizes for complex, video-like animations can be massive compared to lossy formats like WebP or AVIF
  • Was initially rejected by the official PNG group, delaying its adoption for nearly a decade
  • Lacks native hardware decoding acceleration, unlike video-based animated formats (like MP4 or WebM)
DICOM-RLE

DICOM-RLE Strengths

  • Guarantees lossless preservation of critical medical data necessary for diagnostics
  • Extremely robust metadata structure containing patient information, modality, and spatial geometry
  • Faster to encode and decode than complex compression schemes like JPEG 2000
Limitations
  • RLE compression offers very low compression ratios compared to modern codecs like JPEG-LS or JPEG 2000
  • Zero support in web browsers or standard consumer image viewers
  • Strict data privacy regulations (HIPAA/GDPR) make handling DICOM files complex due to embedded PHI

When to choose which format

APNG
Use APNG when…
  • High-Quality Web Animations
  • Stickers (Apple iMessage, LINE, Discord)
  • UI Loaders with Alpha Transparency
  • GIF Replacement
DICOM-RLE
Use DICOM-RLE when…
  • Medical Imaging
  • Ultrasound
  • X-Rays / CT / MRI
  • PACS Archives

More comparisons

APNG vs ACES → DICOM-RLE vs ACES → APNG vs AVCI → DICOM-RLE vs AVCI → APNG vs AVCS → DICOM-RLE vs AVCS → APNG vs AVIF → DICOM-RLE vs AVIF → All comparisons →
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